Natural antifungals activation

A convenient procedure for the lactonization of alkenols has been recently revealed by Borhan and coworkers [19]. This methodology was successfully applied in the total synthesis of (+)-tanikolide (7-37), a natural product of marine origin which exhibits antifungal activities. Thus, when alkenol 7-36 is subjected to soluble oxone and a catalytic amount of 0s04, a smooth domino oxidative cleavage/lactonization process takes place which leads, after debenzylation, to the desired product in good overall yield (Scheme 7.12). 

The cyclosporins are a group of cyclic peptides produced by fungi such as Cylindrocarpon lucidum and Tolypocladium inflatum. These agents show a rather narrow range of antifungal activity, but high levels of immunosuppressive and anti-inflammatory activities. The main component from the culture extracts is cyclosporin A, but some 25 naturally occurring cyclosporins have been characterized. 

In 1988, Nakamura et al. reported the isolation of carbazomycins G (269) and H (270) from the culture broth of Streptoverticillium ehimense. These alkaloids have a structurally unique carbazole-l,4-quinol framework and were obtained from Nature in racemic form. Carbazomycin G showed moderate antifungal activity against... 

In 1990, Isono et al. reported the isolation of RK-286C (318) from the culture filtrate and the mycelium extract of Streptomyces sp. RK-286 (303). In nature, this isolate was obtained in its optically active form [a]p -I- 45.3 (c 0.22, EtOAc). Based on similar CD curves, the absolute configuration of this isolate was assigned to be similar to that of (-E)-staurosporine (295) (see Scheme 2.74) (284). RK-286C has shown PKC inhibitory activity and platelet aggregation in vitro, as well as weak antifungal activity (303). 

Highlights of Research on Plant-Derived Natural Products and Their Analogs with Antitumor, Anti-HIV, and Antifungal Activity ... 

Six-membered rings containing three or more heteroatoms do not occur widely in Nature. The 1,2,4-dithiazine ring occurs in the epidithiodioxopiperazine system (257), which is common to a number of fungal metabolites, such as gliotoxin (258), and appears to be the site of the potent antiviral, antibacterial and antifungal activities of these compounds. However, the compounds are probably better considered as diketopiperazines rather than... 

Zaragozic Acids The zaragozic acids (squalestatins) are a class of competitive inhibitors of mouse, rat, and HepG2 squalene synthases, which also display antifungal activity [104]. The characteristic structural feature of this family of natural products is its highly oxygenated core. 

The observed data reveals that these spiro-(3-lactams are antifungal in nature and the introduction of chloro, methyl and methoxy group further enhances the antifungal activity whereas, nitro group reduces it. The spiro-(3-lactams I were also found to exhibit strong antibacterial activity against E. coli, S. typhi, and B. aureus. 

Ligon JM, Hill DS, Flammer PE, Torkewitz NR, Hofmann D, Kempf H-J, van Pee K-H (2000) Natural Products with Antifungal Activity from Pseudomonas Biocontrol Bacteria. Pest Manag Sci 56 688... 

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